I have never been hesitant to read about Jainism and its take on things like meditation or dhyâna, having learned that Jainism and Buddhism are not that much apart when looked at in their early period (Nakamura). We have to always keep in mind that both Buddhism and Jainism came into existence at about the same time. The Buddha and Mahavira were contemporaries.
Early Buddhism and Jaina writings use many of the same words although not all meanings are the same. Some, however, are the same such as samsara which is undesirable and is without a first beginning for both systems. Both systems agree that our true nature is hidden by ignorance which is the root of samsara.
The idea of self-nature or essence, which in Sanskrit and Pali is svabhâva/sabhâva refers to the pure essence of self (âtman) in Jaina works. It does not refer to the impure jiva which is somewhat like the Buddhist viññâna/vijñâna (consciousness). Toying around with the Jaina notion of svabhâva, I have substituted Pali sabhâva, in this Buddhist passage about the Five Aggregates, with “the pure self” which is Jain. It is not farfetched to consider sabhâva and self as fungible.
“Born materiality is empty of the pure self; disappeared materiality is both changed and empty. Born feeling is empty of the pure self; disappeared feeling is both changed and empty ... Born conceptualization ... Born volitions ... Born consciousness ... Born becoming is empty of the pure self; disappeared becoming is both changed and empty. This is ‘empty in terms of change’” (Patisambhidamagga ii.178 in the Treatise on Voidness).
What I have rendered differently, fits well with many Buddhist passages in the Nikayas in which we learn that the five skandha/khandha are not the self nor is a disciple to regard them as their self.
Turning to the idea of "disciplines" in early Buddhism, according to Nakamura it "was very simple, and similar to those of Jainism." Later, Buddhism coined the new term, patimokkha which early on had to do more with the liberation of mind (cittassa) from samsara (UdA 223–24) than a collection of specific rules. Only much later did patimokkha become associated with monastic regula. The simple portrayal of the ideal Buddhist monk, which is quite early, is to be found in the Sutta-Nipata in the Tuvataka Sutta (beginning with passage 935). The passages are similar to those in Jainism according to Nakamura.
I am of the opinion that Jainism can be of help in making certain aspects of Buddhism clearer, at least in early Buddhist thought.